// 抽象类 只能被继承 不能被实例化

export {}

abstract class Animal {
    eat(food:string):void{
        console.log(`呼噜呼噜的吃:${food}`)
    }
    abstract run(distance: number):void
}

class Dog extends Animal {
    run(distance: number): void {
        console.log(`四脚爬行:${distance}`)
    }
    
}